U.S. patent number 10,427,547 [Application Number 15/679,360] was granted by the patent office on 2019-10-01 for quick charging device.
This patent grant is currently assigned to YAZAKI CORPORATION. The grantee listed for this patent is Yazaki Corporation. Invention is credited to Takahiro Syouda.
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United States Patent |
10,427,547 |
Syouda |
October 1, 2019 |
Quick charging device
Abstract
During charging, a quick charging device forms a battery module
series circuit by connecting a third contact of a first switch to a
second contact of the first switch, and connecting a fifth contact
of a second switch to a twelfth contact of the second switch, so as
to enable a charger to be connected to the battery module series
circuit. During discharging, the quick charging device forms a
battery module parallel circuit by connecting the third contact of
the first switch to a first contact of the first switch, and
connecting the fifth contact of the second switch to a fourth
contact of the second switch, so as to enable a load unit to be
connected to the battery module parallel circuit.
Inventors: |
Syouda; Takahiro (Shizuoka,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Yazaki Corporation |
Tokyo |
N/A |
JP |
|
|
Assignee: |
YAZAKI CORPORATION (Tokyo,
JP)
|
Family
ID: |
61166838 |
Appl.
No.: |
15/679,360 |
Filed: |
August 17, 2017 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180056798 A1 |
Mar 1, 2018 |
|
Foreign Application Priority Data
|
|
|
|
|
Aug 25, 2016 [JP] |
|
|
2016-164949 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60L
53/62 (20190201); B60L 53/14 (20190201); B60L
58/15 (20190201); H02J 7/0019 (20130101); H02J
7/0024 (20130101); H02J 7/0027 (20130101); B60L
53/11 (20190201); B60L 58/19 (20190201); Y02T
10/70 (20130101); Y02T 10/7072 (20130101); Y02T
90/14 (20130101); Y02T 90/12 (20130101); B60L
2210/40 (20130101); B60L 2240/54 (20130101) |
Current International
Class: |
H02J
7/00 (20060101); B60L 53/30 (20190101); B60L
53/10 (20190101); B60L 58/19 (20190101); B60L
58/12 (20190101); B60L 53/14 (20190101); B60L
53/60 (20190101); H02J 7/14 (20060101) |
Field of
Search: |
;320/117,119,118,107,108,109,116,121,126,127,134,162 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Pacheco; Alexis B
Attorney, Agent or Firm: Kenealy Vaidya LLP
Claims
What is claimed is:
1. A quick charging device comprising: a first battery module and a
second battery module that store therein power, the first battery
module includes a plurality of first battery cells, and the second
battery module includes a plurality of second battery cells; a
first switch that has a first contact that is connected to a
positive electrode of the first battery module, a second contact
that is connected to a negative electrode of the first battery
module, and a third contact that is connected to a positive
electrode of the second battery module, and that switches to
connect the third contact to the first contact or the second
contact; a second switch that has a fourth contact that is
connected to the negative electrode of the first battery module,
and a fifth contact that is connected to a negative electrode of
the second battery module, and switches between a connected state
in which the fifth contact is connected to the fourth contact and a
disconnected state; and a controller that controls connections of
the first switch and the second switch, wherein the controller
forms, in a charging operation, a battery module series circuit in
which the negative electrode of the first battery module and the
positive electrode of the second battery module are connected in
series by connecting the third contact of the first switch to the
second contact of the first switch and by switching the second
switch to the disconnected state, so as to enable a charger for
charging the first battery module and the second battery module to
be connected to the battery module series circuit, the controller
forms, in a discharging operation, a battery module parallel
circuit in which the positive electrode of the first battery module
is connected to the positive electrode of the second battery module
and the negative electrode of the first battery module is connected
to the negative electrode of the second battery module by
connecting the third contact of the first switch to the first
contact of the first switch and by connecting the fifth contact of
the second switch to the fourth contact of the second switch, so as
to enable a load unit to be connected to the battery module
parallel circuit, and the controller, in the charging operation,
equalizes a potential difference between the first battery module
and the second battery module by causing a first one of the first
battery cells or a first one of the second battery cells that has a
higher voltage than a remainder of the first battery cells or a
remainder of the second battery cells, respectively, to transfer
power to the remainder of the first battery cells or to the
remainder of the second battery cells, respectively.
2. A quick charging device comprising: a first battery module and a
second battery module that store therein power; a first switch that
has a first contact that is connected to a positive electrode of
the first battery module, a second contact that is connected to a
negative electrode of the first battery module, and a third contact
that is connected to a positive electrode of the second battery
module, and that switches to connect the third contact to the first
contact or the second contact; a second switch that has a fourth
contact that is connected to the negative electrode of the first
battery module, and a fifth contact that is connected to a negative
electrode of the second battery module, and switches between a
connected state in which the fifth contact is connected to the
fourth contact and a disconnected state; a controller that controls
connections of the first switch and the second switch; and a
voltage adjusting unit that adjusts, when there is a potential
difference between the first battery module and the second battery
module, the potential difference to a value equal to or lower than
a preset reference value, wherein the controller forms, in a
charging operation, a battery module series circuit in which the
negative electrode of the first battery module and the positive
electrode of the second battery module are connected in series by
connecting the third contact of the first switch to the second
contact of the first switch and by switching the second switch to
the disconnected state, so as to enable a charger for charging the
first battery module and the second battery module to be connected
to the battery module series circuit, and the controller forms, in
a discharging operation, a battery module parallel circuit in which
the positive electrode of the first battery module is connected to
the positive electrode of the second battery module and the
negative electrode of the first battery module is connected to the
negative electrode of the second battery module by connecting the
third contact of the first switch to the first contact of the first
switch and by connecting the fifth contact of the second switch to
the fourth contact of the second switch, so as to enable a load
unit to be connected to the battery module parallel circuit.
3. The quick charging device according to claim 2, wherein the
voltage adjusting unit includes an additional charging/discharging
unit that adjusts the potential difference to a value equal to or
lower than the reference value by additionally charging or
discharging one of the first battery module and the second battery
module.
4. The quick charging device according to claim 2, wherein the
voltage adjusting unit includes an additional charging unit that
adjusts the potential difference to a value equal to or lower than
the reference value by additionally charging one of the first
battery module and the second battery module whichever having a
lower voltage, and a switching unit including a first switch that
has a sixth contact that is connected to the positive electrode of
the first battery module, a seventh contact that is connected to
the positive electrode of the second battery module, and an eighth
contact that is connected to one side of the additional charging
unit, and that switches to connect the eighth contact to the sixth
contact or the seventh contact, and a second switch that has a
ninth contact that is connected to the negative electrode of the
first battery module, a tenth contact that is connected to the
negative electrode of the second battery module, and an eleventh
contact that is connected to the other side of the additional
charging unit, and switches to connect the eleventh contact to the
ninth contact or the tenth contact.
5. The quick charging device according to claim 3, wherein if a
voltage of the second battery module is lower than a voltage of the
first battery module, and the second battery module includes a
battery cell that is fully charged, the additional
charging/discharging unit charges the first battery module and the
second battery module while discharging the second battery module,
if a voltage of the first battery module is lower than a voltage of
the second battery module, and the first battery module includes a
battery cell that is fully charged, the additional
charging/discharging unit charges the first battery module and the
second battery module while discharging the first battery module.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
The present application claims priority to and incorporates by
reference the entire contents of Japanese Patent Application No.
2016-164949 filed in Japan on Aug. 25, 2016.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a quick charging device.
2. Description of the Related Art
Having been conventionally available is a quick charging device for
quickly charging a storage battery used onboard a vehicle, such as
an electric vehicle (EV). Some quick charging devices charge
storage batteries with a relatively high voltage, for example, to
improve the charging speed. In such a case, the quick charging
device uses a storage battery including a plurality of battery
modules, and connects the battery modules in series to charge the
storage battery, and connects the battery modules in parallel to
discharge the storage battery, for example (see Japanese Patent
Application Laid-open No. 2014-193033, for example).
Such a quick charging device connects the battery modules in series
or in parallel depending on whether the storage battery is to be
charged or discharged, but there is still some room for improvement
in suppressing a loss in power consumption in such operations.
SUMMARY OF THE INVENTION
To address this issue, an object of the present invention is to
provide a quick charging device capable of suppressing a loss in
power consumption.
A quick charging device according to one aspect of the present
invention includes a first battery module and a second battery
module that store therein power; a first switch that has a first
contact that is connected to a positive electrode of the first
battery module, a second contact that is connected to a negative
electrode of the first battery module, and a third contact that is
connected to a positive electrode of the second battery module, and
that switches to connect the third contact to the first contact or
the second contact; a second switch that has a fourth contact that
is connected to the negative electrode of the first battery module,
and a fifth contact that is connected to a negative electrode of
the second battery module, and switches between a connected state
in which the fifth contact is connected to the fourth contact and a
disconnected state; and a controller that controls connections of
the first switch and the second switch, wherein the controller
forms, in a charging operation, a battery module series circuit in
which the negative electrode of the first battery module and the
positive electrode of the second battery module are connected in
series by connecting the third contact of the first switch to the
second contact of the first switch and by switching the second
switch to the disconnected state, so as to enable a charger for
charging the first battery module and the second battery module to
be connected to the battery module series circuit, and the
controller forms, in a discharging operation, a battery module
parallel circuit in which the positive electrode of the first
battery module is connected to the positive electrode of the second
battery module and the negative electrode of the first battery
module is connected to the negative electrode of the second battery
module by connecting the third contact of the first switch to the
first contact of the first switch and by connecting the fifth
contact of the second switch to the fourth contact of the second
switch, so as to enable a load unit to be connected to the battery
module parallel circuit.
According to another aspect of the present invention, the quick
charging device may further includes a voltage adjusting unit that
adjusts, when there is a potential difference between the first
battery module and the second battery module, the potential
difference to a value equal to or lower than a preset reference
value.
According to still another aspect of the present invention, in the
quick charging device, it is preferable that the voltage adjusting
unit includes an additional charging/discharging unit that adjusts
the potential difference to a value equal to or lower than the
reference value by additionally charging or discharging one of the
first battery module and the second battery module.
According to still another aspect of the present invention, in the
quick charging device, it is preferable that the voltage adjusting
unit includes an additional charging unit that adjusts the
potential difference to a value equal to or lower than the
reference value by additionally charging one of the first battery
module and the second battery module whichever having a lower
voltage, and a switching unit including a first switch that has a
sixth contact that is connected to the positive electrode of the
first battery module, a seventh contact that is connected to the
positive electrode of the second battery module, and an eighth
contact that is connected to one side of the additional charging
unit, and that switches to connect the eighth contact to the sixth
contact or the seventh contact, and a second switch that has a
ninth contact that is connected to the negative electrode of the
first battery module, a tenth contact that is connected to the
negative electrode of the second battery module, and an eleventh
contact that is connected to the other side of the additional
charging unit, and switches to connect the eleventh contact to the
ninth contact or the tenth contact.
The above and other objects, features, advantages and technical and
industrial significance of this invention will be better understood
by reading the following detailed description of presently
preferred embodiments of the invention, when considered in
connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit diagram illustrating an exemplary configuration
of a series connection in a quick charging device according to a
first embodiment of the present invention;
FIG. 2 is a circuit diagram illustrating an exemplary configuration
of a parallel connection in the quick charging device according to
the first embodiment;
FIG. 3 is a flowchart illustrating an exemplary operation of the
quick charging device according to the first embodiment;
FIG. 4 is a circuit diagram illustrating an exemplary configuration
of the quick charging device according to a second embodiment of
the present invention;
FIG. 5 is a flowchart illustrating an exemplary operation of the
quick charging device according to the second embodiment;
FIG. 6 is a circuit diagram illustrating an exemplary configuration
of the quick charging device according to a third embodiment of the
present invention; and
FIG. 7 is a flowchart illustrating an exemplary operation of the
quick charging device according to the third embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Some embodiment for implementing the present invention will now be
explained in detail with reference to some drawings. The
descriptions in the following embodiments are not intended to limit
the scope of the present invention in any way. Some of the elements
described below include those that can be easily thought of by
those skilled in the art, and those substantially the same.
Furthermore, the configurations described below may be combined as
appropriate. Furthermore, various types of omissions, replacement,
or modifications are still possible within the scope not deviating
from the spirit of the present invention.
First Embodiment
A quick charging device 1 according to a first embodiment of the
present invention will now be explained. The quick charging device
1 is for quickly charging a storage battery 10. Explained in this
embodiment is an example in which the quick charging device 1
charges a storage battery 10 provided onboard a vehicle 2 such as
an electric vehicle (EV), a plug-in hybrid electric vehicle (PHEV),
or a hybrid electric vehicle (HEV). The quick charging device 1
will now be explained in detail.
The quick charging device 1 charges the power of the storage
battery 10 onboard the vehicle 2, for example. The quick charging
device 1 includes, as illustrated in FIG. 1, the storage battery
10, a switching unit 20, and a controller 30. The quick charging
device 1 is connected to an external charger (quick charger) 3 over
a wire harness 4, for example, and charges the storage battery 10
by receiving a power supply from the charger 3. The external
charger 3 is installed in a quick charging station or the like not
illustrated, for example. The quick charging device 1 supplies the
power charged in the storage battery 10 to an inverter 5a and a
motor generator (MG) 5b that are load units 5. For example, the
quick charging device 1 has the storage battery 10 connected to the
motor generator 5b via the inverter 5a, and the inverter 5a
converts the direct current from the storage battery 10 into an
alternating current, and the alternating current is supplied to the
motor generator 5b.
The storage battery 10 is a battery in which the power is stored.
The storage battery 10 supplies the stored power to the load unit
5. The storage battery 10 is a lithium-ion battery, for example,
and includes a plurality of battery modules 11. In this example,
the storage battery 10 includes two battery modules 11. Each of the
battery modules 11 is referred to as a first battery module 11A or
a second battery module 11B. To enable the storage battery 10 to be
charged quickly, the two battery modules 11 are connected in
different configurations depending on whether the storage battery
10 is to be charged or discharged. For example, to charge the
storage battery 10, the first battery module 11A and the second
battery module 11B are connected in series, and to discharge the
storage battery 10, the first battery module 11A and the second
battery module 11B are connected in parallel. In this manner, the
storage battery 10 can be charged with a voltage about twice the
voltage at which the storage battery 10 is discharged, and
therefore, the storage battery 10 can be quickly charged. During
charging, the positive electrode of the storage battery 10 is
connected to the negative electrode of the charger 3, and the
negative electrode is connected to the positive electrode of the
charger 3. During discharging, the positive electrode of the
storage battery 10 is connected to the negative electrode of the
load unit 5, and the negative electrode is connected to the
positive electrode of the load unit 5. Each of the battery modules
11 provided to the storage battery 10 includes a plurality of
battery cells 11a, 11b. In this example, each of the battery cells
11a, 11b has the same voltage. Each of the battery modules 11
includes the same number of battery cells 11a, 11b. In each of the
battery modules 11, several tens to several hundreds of battery
cells 11a, 11b are connected in series, for example. The voltage VA
of the first battery module 11A having all of the battery cells 11a
fully charged is equivalent to the voltage VB of the second battery
module 11B having all of the battery cells 11b fully charged.
The switching unit 20 is a switch for switching the current path
through which the current flows. The switching unit 20 switches the
current path based on a switching signal issued by the controller
30 which will be described later. The switching unit 20 connects
the first battery module 11A and the second battery module 11B in
series, and forms the path for the current flowing from the charger
3 into the first battery module 11A and the second battery module
11B. The switching unit 20 also connects the first battery module
11A and the second battery module 11B in parallel, and forms a path
for the current flowing from the first battery module 11A and the
second battery module 11B into the load unit 5. The switching unit
20 includes a first switch 21 and a second switch 22. The first
switch 21 has a first contact 21a that is connected to the positive
electrode of the first battery module 11A, a second contact 21b
that is connected to the negative electrode of the first battery
module 11A, and a third contact 21c that is connected to the
positive electrode of the second battery module 11B, and switches
to connect the third contact 21c to the first contact 21a or the
second contact 21b. The second switch 22 has a fourth contact 22a
that is connected to the negative electrode of the first battery
module 11A, a fifth contact 22c that is connected to the negative
electrode of the second battery module 11B, and a twelfth contact
22b that breaks the electrical connection, and switches between a
connected state in which the fifth contact 22c is connected to the
fourth contact 22a, and a disconnected state in which the fifth
contact 22c is connected to the twelfth contact 22b.
The controller 30 is connected to the switching unit 20, and
controls the switching unit 20. The controller 30 includes an
electronic circuit mainly having a known micro-computer including a
central processing unit (CPU), a read-only memory (ROM) and a
random access memory (RAM) providing a storage unit, and an
interface. The controller 30 outputs a switching signal to the
switching unit 20, and forms the battery module series circuit P
when the storage battery 10 is to be charged, and forms the battery
module parallel circuit Q when the storage battery 10 is to be
discharged.
When the switching signal indicates to charge, the switching unit
20 connects the third contact 21c on the positive electrode side of
the second battery module 11B to the second contact 21b on the
negative electrode side of the first battery module 11A, and
connects the fifth contact 22c on the negative electrode side of
the second battery module 11B to the twelfth contact 22b. The
switching unit 20 thus forms the battery module series circuit P in
which the negative electrode of the first battery module 11A and
the positive electrode of the second battery module 11B are
connected in series by the first switch 21 so as to enable the
charger 3 to be connected to the battery module series circuit P.
In other words, the switching unit 20 connects the negative
electrode of the charger 3 to the positive electrode of the battery
module series circuit P and connects the positive electrode of the
charger 3 to the negative electrode of the battery module series
circuit P. In this manner, the quick charging device 1 can charge
the storage battery 10 at a voltage higher than a voltage about
twice, for example, that used in discharging the storage battery
10.
When the switching signal indicates to discharge, the switching
unit 20 connects, as illustrated in FIG. 2, the first contact 21a
on the positive electrode side of the first battery module 11A to
the third contact 21c on the positive electrode side of the second
battery module 11B, and connects the fifth contact 22c on the
negative electrode side of the second battery module 11B to the
fourth contact 22a on the negative electrode side of the first
battery module 11A. The switching unit 20 thus forms the battery
module parallel circuit Q in which the positive electrode of the
first battery module 11A and the positive electrode of the second
battery module 11B are connected by the first switch 21, and the
negative electrode of the first battery module 11A and the negative
electrode of the second battery module 11B are connected by the
second switch 22, so as to enable the load unit 5 to be connected
to the battery module parallel circuit Q. In other words, the
switching unit 20 connects the negative electrode of the load unit
5 to the positive electrode of the battery module parallel circuit
Q, and connects the positive electrode of the load unit 5 to the
negative electrode of the battery module parallel circuit Q. In
this manner, the quick charging device 1 can discharge the storage
battery 10 with a voltage lower than a half or so, for example,
that used in charging the storage battery 10.
An exemplary operation of the quick charging device 1 will now be
explained with reference to FIG. 3. The quick charging device 1
determines whether charging has started (Step S1). For example, the
quick charging device 1 determines that charging has started if the
charger 3 has been connected, and a signal for starting quick
charging has been output from the charger 3. If the quick charging
device 1 determines that charging has started (Yes at Step S1), the
quick charging device 1 switches the switching unit 20 to form the
battery module series circuit P (Step S2). The quick charging
device 1 then causes the charger 3 to apply current to the battery
module series circuit P, and charges each of the battery modules 11
that are connected in series (Step S3). At this time, the quick
charging device 1 monitors the voltage of each of the battery cells
11a, 11b included in the first battery module 11A and the second
battery module 11B using a cell voltage sensor (CVS), and equalizes
the voltages of the respective battery cells 11a, 11b by causing a
battery cell 11a, 11b having reached a voltage higher than that of
the other battery cells 11a, 11b to discharge into a resistance or
to transfer the power to the other battery cells 11a, 11b. In this
manner, the quick charging device 1 can equalize the potential
difference between the first battery module 11A and the second
battery module 11B. This configuration enables the quick charging
device 1 to connect the first battery module 11A and the second
battery module 11B in parallel during a discharge operation,
without using a resistance, for example, in the manner having been
conventionally practiced. The charger 3 adjusts its output voltage
so as to charge the storage battery 10 at a predetermined C rate (a
current with respect to the battery capacity), based on the voltage
of the battery module series circuit P.
The quick charging device 1 detects the voltage of the battery
modules 11 using a voltage detecting unit not illustrated, and
determines whether the voltages of the respective battery modules
11 are substantially equal (Step S4). If the voltages of the
respective battery modules 11 are substantially equal (Yes at Step
S4), the quick charging device 1 determines whether the charging
has been completed (Step S5). For example, the quick charging
device 1 determines whether at least one of the battery modules 11
has reached a charging ending voltage. If at least one of the
battery modules 11 has reached the charging ending voltage, and the
charging has been completed (Yes at Step S5), the quick charging
device 1 stops the power supply from the charger 3, forms the
battery module parallel circuit Q, and ends the process (Step S6).
The charging ending voltage herein is a voltage indicating that the
charging has been completed, and is a predetermined voltage for
preventing overcharge.
At Step S1 described above, if the quick charging device 1
determines that the charging has not been started yet (No at Step
S1), the quick charging device 1 determines whether charging has
started, again. At Step S4 described above, if the voltages of the
respective battery modules 11 are not substantially equal (No at
Step S4), the quick charging device 1 shifts the process back to
Step S3, and charges the battery modules 11 while equalizing the
voltages of the respective battery cells 11a, 11b. At Step S5
described above, if none of the battery modules 11 has reached the
charging ending voltage, and the charging has not been completed
yet (No at Step S5), the quick charging device 1 shifts the process
back to Step S3, and charges the battery modules 11 while
equalizing the voltages of the respective battery cells 11a,
11b.
As described above, to charge the storage battery 10, by connecting
the third contact 21c of the first switch 21 to the second contact
21b of the first switch 21, and connecting the fifth contact 22c of
the second switch 22 to the twelfth contact 22b of the second
switch 22, the quick charging device 1 according to the first
embodiment can form the battery module series circuit P in which
the negative electrode of the first battery module 11A is connected
to the positive electrode of the second battery module 11B in
series, so as to enable the charger 3 to be connected to the
battery module series circuit P. Furthermore, to discharge the
storage battery 10, by connecting the third contact 21c of the
first switch 21 to the first contact 21a of the first switch 21,
and connecting the fifth contact 22c of the second switch 22 to the
fourth contact 22a of the second switch 22, the quick charging
device 1 can form the battery module parallel circuit Q in which
the positive electrode of the first battery module 11A is connected
to the positive electrode of the second battery module 11B and the
negative electrode of the first battery module 11A is connected to
the negative electrode of the second battery module 11B, so as to
enable the load unit 5 to be connected to the battery module
parallel circuit Q. In this manner, the quick charging device 1 can
form the battery module series circuit P and the battery module
parallel circuit Q using the first switch 21 and second switch 22,
so that these circuits can be achieved with minimum switches
required, and the power loss can be suppressed. Furthermore,
because the quick charging device 1 charges the battery modules
with a high voltage using the battery module series circuit P, the
amount of power can be increased without increasing the current. In
this manner, the quick charging device 1 can suppress the power
loss resulting from an increased current, and can also suppress
heating of the wire harness 4 and the like.
Modification of First Embodiment
The quick charging device 1 may also generate, for regenerative
braking, a regenerative voltage using a motor generator 5b, boost
the regenerative voltage using a converter 5c, and charge the power
to the storage battery 10.
Furthermore, explained above is an example in which the storage
battery 10 includes two battery modules 11, but the storage battery
may also include more than two battery modules 11. Furthermore,
explained above is an example in which the battery cells 11a, 11b
included in the storage battery 10 have the same voltage, but may
also have different voltage.
Second Embodiment
A quick charging device 11A according to a second embodiment of the
present invention will now be explained. The quick charging device
11A according to the second embodiment is different from the quick
charging device 1 according to the first embodiment in being
provided with a voltage adjusting unit 40 that adjusts the
potential difference between the battery modules 11, as illustrated
in FIG. 4. In the second embodiment, elements that are the same as
those according to the first embodiment will be given the same
reference numerals as those in the first embodiment, and detailed
explanations thereof will be omitted.
The voltage adjusting unit 40 is for adjusting the potential
difference between the first battery module 11A and the second
battery module 11B. If there is any potential difference between
the first battery module 11A and the second battery module 11B
during or after the quick charging, the voltage adjusting unit 40
adjusts the potential difference to a value equal to or lower than
the preset reference value. Adjusting the potential difference to a
value equal to or lower than the preset reference value means to
keep the current flowing through the battery module parallel
circuit Q within a range (current upper boundary) not adversely
affecting the quick charging device 1A or the load unit 5, for
example. The current in the quick charging device 1A is determined
by resistance components, such as the battery modules 11, the wire
harness 4, and the switching unit 20 included in the battery module
parallel circuit Q, and on the potential difference between the
battery modules 11. The quick charging device 1A needs to keep the
current that is caused to flow by the potential difference between
the battery modules 11 to a value equal to or lower than the
current upper boundary of the battery module parallel circuit
Q.
In the second embodiment, the voltage adjusting unit 40 serves as
additional charging/discharging unit 41 performing additional
charging or discharging. The additional charging/discharging unit
41 is connected to the positive electrode and the negative
electrode of the charger 3, and is connected to the positive
electrode and the negative electrode of the second battery module
11B. The additional charging/discharging unit 41 includes, for
example, a switch not illustrated for switching ON and OFF the
voltage to be additionally applied from the charger 3 to the second
battery module 11B, and a load unit not illustrated for discharging
the second battery module 11B. The additional charging/discharging
unit 41 adjusts the potential difference to a value equal to or
lower than the reference value by additionally charging or
discharging the second battery module 11B. The additional
charging/discharging unit 41 may also be connected to the first
battery module 11A, instead of the second battery module 11B, and
may adjust the potential difference to a value equal to or lower
than the reference value by additionally charging or discharging
the first battery module 11A.
An exemplary operation of the quick charging device 1A according to
the second embodiment will now be explained with reference to FIG.
5. The quick charging device 1A determines whether charging has
started (Step S1a). For example, the quick charging device 1A
determines that charging has started if the charger 3 has been
connected, and a signal for starting quick charging has been output
from the charger 3. If the quick charging device 1A determines that
charging has started (Yes at Step S1a), the quick charging device
1A switches the switching unit 20 to form the battery module series
circuit P (Step S2a). The quick charging device 1A then causes the
charger 3 to apply current to the battery module series circuit P,
and charges each of the battery modules 11 that are connected in
series (Step S3a). At this time, the quick charging device 1A
monitors the voltage of each of the battery cells 11a, 11b using a
CVS, equalizes the voltage of the battery cells 11a, 11b by causing
a battery cell 11a, 11b having reached a higher voltage than those
of the other battery cells 11a, 11b to discharge into a resistance
or to transfer the power to the other battery cells 11a, 11b.
The quick charging device 1A then determines whether the additional
charging/discharging caused to be performed based on the potential
difference between the battery modules 11 has been completed (Step
S4a). For example, the quick charging device 1A detects the voltage
of each of the battery modules 11 using the voltage detecting unit,
and determines whether the voltages of the respective battery
modules 11 are substantially equal, that is, whether the potential
difference between the battery modules 11 is equal to or lower than
the reference value. If the voltages of the respective battery
modules 11 are not substantially equal, the quick charging device
1A performs the additional charging or discharging, using the
additional charging/discharging unit 41. For example, if the
voltage VB of the second battery module 11B is lower than the
voltage VA of the first battery module 11A, the quick charging
device 1A applies an additional voltage to the second battery
module 11B using the additional charging/discharging unit 41 so
that the voltage VB of the second battery module 11B is increased.
If the voltage VB of the second battery module 11B is higher than
the voltage VA of the first battery module 11A, the quick charging
device 1A discharges the second battery module 11B using the
additional charging/discharging unit 41 so that the voltage VB of
the second battery module 11B is decreased. If the voltages of the
respective battery modules 11 become substantially equal, and the
additional charging/discharging has been completed (Yes at Step
S4a), the quick charging device 1A determines whether the charging
has been completed (Step S5a). For example, the quick charging
device 1A determines whether at least one of the battery modules 11
has reached the charging ending voltage. If at least one of the
battery modules 11 has reached the charging ending voltage, and the
charging has been completed (Yes at Step S5a), the quick charging
device 1A stops the power supply from the charger 3, forms the
battery module parallel circuit Q, and ends the process (Step
S6a).
At Step S1a described above, if the quick charging device 1A
determines that charging has not started yet (No at Step S1a), the
quick charging device 1A determines whether charging has started,
again. At Step S4a described above, if the voltages of the
respective battery modules 11 are not substantially equal and the
additional charging/discharging has not been completed (No at Step
S4a), the quick charging device 1A shifts the process back to Step
S1a, and charges the battery modules 11. At Step S5a described
above, if none of the battery modules 11 has reached the charging
ending voltage, and the charging has not been completed yet (No at
Step S5a), the quick charging device 1A shifts the process back to
Step S1a, and charges the battery modules 11.
If the voltage VB of the second battery module 11B is lower than
the voltage VA of the first battery module 11A, and the second
battery module 11B includes a battery cell 11b that is fully
charged, the quick charging device 1A charges the first battery
module 11A and the second battery module 11B while discharging the
second battery module 11B using the additional charging/discharging
unit 41. This is because, although the voltage VB needs to be
boosted because the voltage VB is lower than the voltage VA, but
the second battery module 11B cannot be charged any further because
the second battery module 11B includes the battery cell 11b that is
fully charged. Therefore, the first battery module 11A and the
second battery module 11B are charged while discharging the second
battery module 11B.
As described above, the quick charging device 1A according to the
second embodiment includes the voltage adjusting unit 40 that
adjusts, when there is any potential difference between the first
battery module 11A and the second battery module 11B before the
battery module parallel circuit Q is formed, the potential
difference to a value equal to or lower than the preset reference
value. In this manner, because the quick charging device 1A
equalizes the voltage of the battery cells 11a, 11b included in the
respective battery modules 11, and adjusts the potential difference
in units of the battery module 11, the potential difference between
the battery modules 11 can be adjusted to a value equal to or lower
than the reference value in a short time period. Furthermore, the
quick charging device 1A can reduce a power loss, and adjust the
potential difference in a shorter time period, compared with a
configuration in which the potential difference between a plurality
of battery modules 11 is adjusted using a resistance, as has been
conventionally practiced.
Furthermore, the additional charging/discharging unit 41 adjusts
the potential difference between the first battery module 11A and
the second battery module 11B to a value equal to or lower than the
reference value, by additionally charging or discharging one of the
first battery module 11A and the second battery module 11B, which
is, in this example, the second battery module 11B. In this manner,
because the quick charging device 1A additionally charges or
discharges one of the first battery module 11A and the second
battery module 11B, the circuit configuration or the like can be
simplified, compared with a configuration in which both of the
first battery module 11A and the second battery module 11B are
additionally charged, for example.
Third Embodiment
A quick charging device 1B according to a third embodiment of the
present invention will now be explained. The quick charging device
1B according to the third embodiment is different from the quick
charging device 1 according to the first embodiment in being
provided with the voltage adjusting unit 40 that adjusts the
potential difference between the battery modules 11, as illustrated
in FIG. 6. In the third embodiment, elements that are the same as
those according to the first embodiment will be given the same
reference numerals as those in the first embodiment, and detailed
explanations thereof will be omitted.
In the third embodiment, the voltage adjusting unit 40 includes an
additional charging unit 42 that performs additional charging, and
a switching unit 50. The additional charging unit 42 is connected
to the positive electrode and the negative electrode of the charger
3. The additional charging unit 42 is connected to the positive
electrode and the negative electrode of the first battery module
11A, and is connected to the positive electrode and the negative
electrode of the second battery module 11B. The additional charging
unit 42 includes, for example, a switch not illustrated for turning
ON and OFF the voltage to be additionally applied to each of the
battery modules 11 by the charger 3. The additional charging unit
42 adjusts the potential difference to a value equal to or lower
than the reference value by additionally charging one of the first
battery module 11A and the second battery module 11B, whichever
having a lower voltage.
The switching unit 50 includes a first switch 51 and a second
switch 52. The first switch 51 has a sixth contact 51a that is
connected to the positive electrode of the first battery module
11A, a seventh contact 51b that is connected to the positive
electrode of the second battery module 11B, and an eighth contact
51c that is connected to one side of the additional charging unit
42, and switches to connect the eighth contact 51c to the sixth
contact 51a or the seventh contact 51b. The second switch 52 has a
ninth contact 52a that is connected to the negative electrode of
the first battery module 11A, a tenth contact 52b that is connected
to the negative electrode of the second battery module 11B, and an
eleventh contact 52c that is connected to the other side of the
additional charging unit 42, and switches to connect the eleventh
contact 52c to the ninth contact 52a or the tenth contact 52b.
The switching unit 50 connects the eleventh contact 52c of the
additional charging unit 42 to the ninth contact 52a on the
negative electrode side of the first battery module 11A, and
connects the eighth contact 51c of the additional charging unit 42
to the sixth contact 51a on the positive electrode side of the
first battery module 11A, based on the switching signal. In this
manner, the switching unit 50 connects the additional charging unit
42 to the first battery module 11A.
The switching unit 50 also connects the eleventh contact 52c of the
additional charging unit 42 to the tenth contact 52b on the
negative electrode side of the second battery module 11B, and
connects the eighth contact 51c of the additional charging unit 42
to the seventh contact 51b on the positive electrode side of the
second battery module 11B, based on the switching signal. In this
manner, the switching unit 50 connects the additional charging unit
42 to the second battery module 11B.
An exemplary operation of the quick charging device 1B according to
the third embodiment will now be explained with reference to FIG.
7. The quick charging device 1B determines whether charging has
started (Step S1b). For example, the quick charging device 1B
determines that charging has started if the charger 3 has been
connected, and a signal for starting quick charging has been output
from the charger 3. If the quick charging device 1B determines that
charging has started (Yes at Step S1b), the quick charging device
1B switches the switching unit 20 to form the battery module series
circuit P (Step S2b). The quick charging device 1B then causes the
charger 3 to apply current to the battery module series circuit P,
and charges each of the battery modules 11 that are connected in
series (Step S3b). At this time, the quick charging device 1B
monitors the voltage of each of the battery cells 11a, 11b using a
CVS, and equalizes the voltage of the battery cells 11a, 11b by
causing a battery cell 11a, 11b having reached a higher voltage
than those of the other battery cells 11a, 11b to discharge into a
resistance or to transfer the power to the other battery cells 11a,
11b.
The quick charging device 1B then determines whether the charging
has been completed (Step S4b). For example, the quick charging
device 1B determines whether at least one of the battery modules 11
has reached the charging ending voltage. If at least one of the
battery modules 11 has reached the charging ending voltage, and the
charging has been completed (Yes at Step S4b), the quick charging
device 1B compares the voltages of the respective battery modules
11 (Step S5b). If the voltage VA of the first battery module 11A is
lower than the voltage VB of the second battery module 11B
(VA<VB), the quick charging device 1B connects the additional
charging unit 42 to the first battery module 11A, and additionally
charges the first battery module 11A. If the voltages of the
respective battery modules 11 become substantially equal, that is,
if the potential difference between the battery modules 11 becomes
equal to or lower than the reference value, and additional charging
has been completed (Yes at Step S6b), the quick charging device 1B
stops the power supply from the charger 3, forms the battery module
parallel circuit Q, and ends the process (Step S8b). If the voltage
VB of the second battery module 11B is lower than the voltage VA of
the first battery module 11A (VA>VB), the quick charging device
1B connects the additional charging unit 42 to the second battery
module 11B, and additionally charges the second battery module 11B.
If the voltages of the respective battery modules 11 become
substantially equal, and the additional charging is completed (Yes
at Step S7b), the quick charging device 1B stops the power supply
from the charger 3, forms the battery module parallel circuit Q,
and ends the process (Step S8b). If the voltage VA of the first
battery module 11A is substantially the same as the voltage VB of
the second battery module 11B (VA=VB), the quick charging device 1B
stops the power supply from the charger 3, forms the battery module
parallel circuit Q, and ends the process (Step S8b).
At Step S1b described above, if the quick charging device 1B
determines that charging has not started yet (No at Step S1b), the
quick charging device 1B determines whether charging has started,
again. At Step S4b described above, if none of the battery modules
11 has reached the charging ending voltage, and the charging has
not been completed yet (No at Step S4b), the quick charging device
1B shifts the process back to Step S1b, and charges the battery
modules 11. At Step S6b described above, if the additional charging
has not been completed yet (No at Step S6b), the quick charging
device 1B shifts the process back to Step S5b, and compares the
voltages of the respective battery modules 11. At Step S7b
described above, if the additional charging has not been completed
yet (No at Step S7b), the quick charging device 1B shifts the
process back to Step S5b, and compares the voltages of the
respective battery modules 11.
As described above, the quick charging device 1B according to the
third embodiment adjusts the potential difference to a value equal
to or lower than the reference value by additionally charging one
of the first battery module 11A and the second battery module 11B,
whichever having a lower voltage. In this manner, because the quick
charging device 1B equalizes the voltage of the battery cells 11a,
11b included in the battery modules 11, and adjusts the potential
difference in units of the battery module 11, the potential
difference between the battery modules 11 can be adjusted to a
value equal to or lower than the reference value in a short time
period. Furthermore, because the quick charging device 1B does not
adjust the potential difference by discharging, as the quick
charging device 1A according to the second embodiment, the power
loss can be reduced.
Modification of Third Embodiment
Explained above is an example in which the voltage adjusting unit
40 serves as the additional charging unit 42 performing additional
charging, but the present invention is not limited thereto. The
voltage adjusting unit 40 may also serve as a discharging unit for
discharging. In such a configuration, the discharging unit adjusts
the potential difference to a value equal to or lower than the
reference value by connecting to the first battery module 11A or
the second battery module 11B, and discharging the first battery
module 11A or the second battery module 11B whichever having a
higher voltage.
Furthermore, the quick charging device 1B performs the additional
charging after the charging is completed, but the present invention
is not limited thereto. The quick charging device 1B may perform
the additional charging while the battery modules are being
charged. In such a case, the quick charging device 1B can reduce
the time required for charging, because the voltage VA of the first
battery module 11A will be substantially the same as the voltage VB
of the second battery module 11B by the time at which the charging
of these battery modules is completed.
The quick charging device 1 may include the battery modules 11
including the battery cells 11a, 11b, a switching unit 20 that
switches to form the battery module series circuit P in which the
battery modules 11 are connected in series so as to enable the
charger 3 is for charging the battery modules 11 to be connected to
the battery module series circuit P, and to form the battery module
parallel circuit Q in which the battery modules 11 are connected in
parallel so as to enable the load unit 5 to be connected to the
battery module parallel circuit Q, the controller 30 that controls
the switching unit 20 to switch to the battery module series
circuit P when the battery modules 11 are to be charged, and to the
battery module parallel circuit Q when the battery modules 11 are
to be discharged, and the voltage adjusting unit 40 that adjusts,
when there is a potential difference between the battery modules
11, the potential difference to a value equal to or lower than the
preset reference value before switching to the battery module
parallel circuit Q.
During charging, the quick charging device according to the
embodiments forms the battery module series circuit in which the
negative electrode of the first battery module and the positive
electrode of the second battery module are connected in series by
connecting the third contact of the first switch to the second
contact of the first switch and by disconnecting the second switch,
so as to enable the charger for charging the first battery module
and the second battery module to be connected to the battery module
series circuit. To discharge the storage battery, the quick
charging device forms a battery module parallel circuit in which
the positive electrode of the first battery module is connected to
the positive electrode of the second battery module, and the
negative electrode of the first battery module is connected to the
negative electrode of the second battery module by connecting the
third contact of the first switch to the first contact of the first
switch and by connecting the fifth contact of the second switch to
the fourth contact of the second switch, so as to enable the load
unit to be connected to the battery module parallel circuit. In
this manner, the quick charging device can form a battery module
series circuit and a battery module parallel circuit using the
first switch and the second switch, so that these circuits can be
achieved with the minimum switches required, and a loss in power
consumption can be suppressed.
Although the invention has been described with respect to specific
embodiments for a complete and clear disclosure, the appended
claims are not to be thus limited but are to be construed as
embodying all modifications and alternative constructions that may
occur to one skilled in the art that fairly fall within the basic
teaching herein set forth.
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